1. Field of the Invention
The present invention relates to a laminated iron core in which a skew shape becomes variable after caulking lamination and a manufacturing method of the same.
2. Background Art
In a motor, a rotator laminated iron core formed by caulking and laminating rotator iron core pieces punched out from a metal thin plate by a die apparatus is rotatably incorporated in the inside of a stator laminated iron core formed by caulking and laminating stator iron core pieces punched out from a metal thin plate by the die apparatus.
Incidentally, in order to prevent a cogging phenomenon from occurring at a time of operation of a motor, for example, when the rotator laminated iron core is manufactured, the rotator iron core pieces are caulked and laminated while being skewed.
Here, JP-A-5-56608 discloses a skew formed in such a manner that when a punched rotator iron core piece is laminated on a previously punched rotator iron core piece, caulking lamination is performed while shifting a position of a caulked position by rotating the previously punched rotator iron core piece side by a specified angle (skew angle).
As stated above, although the skew can be simultaneously formed when the rotator iron core pieces are caulked and laminated to form the rotator laminated iron core, the primary object of the caulking lamination is to form the rotator laminated iron core by caulking and joining the respective rotator iron core pieces.
Thus, when the rotator laminated iron core is manufactured, although the skew can be formed as stated above, after the rotator laminated iron core is once manufactured, the skew shape can not be changed.
Further, the skew shape can not be changed in the manufactured rotator laminated iron core, in the case where the use mode or the use object of a motor is changed halfway, measures against that become insufficient, and there is a high possibility that the cogging phenomenon and noise occur at the time of operation of the motor.
The invention has been made in view of such circumstances, and has an object to provide a skew shape variable laminated iron core in which even after caulking lamination, a skew shape can be freely changed according to various uses of a motor, and a manufacturing method of the same.